Trastuzumab is a key therapy for patients with human epidermal growth factor receptor 2 positive breast cancer (BC). However, it may cause left ventricular dysfunction, resulting in withdrawal of therapy. Left atrium (LA) enlargement has proven to cue subclinical ventricular dysfunction in various clinical setting. Aim of the study was to investigate the association between LA volume index (LAVI) change over time and the development of Cancer Therapeutics Related Cardiac Dysfunction (CTRCD). Consecutive human epidermal growth factor receptor 2 positive BC patients were retrospectively included. Transthoracic echocardiography was performed before starting Trastuzumab and at every 3 up to 12 months. LA volume was measured using the modified Simpson's rule and indexed for body surface area. Ninety patients formed the study population. All patients had a complete 12 months follow-up. Mean baseline LAVI was 27 ± 8 ml/m2 and it was dilated (≥34 ml/m2) in 10 patients (11%). During follow-up, CTRCD occurred in 19 (21%) patients and there was modest LAVI enlargement, with a mean increase of 3 ± 2 ml/m2 (p = 0.0002 vs. baseline). LAVI dilation was significantly higher in patients with CTRCD (average increase at the time of CTRCD vs. baseline: 7 ± 6 ml/m2, p = 0.008), versus patients without CTRCD (average increase at 12 months of follow-up 2±1, p = 0.02), p for comparison = 0.004. LAVI dilatation over time predicted CTRCD independently from baseline LAVI values and the presence of systemic arterial hypertension (OR for 5 ml/m2 dilation was 1.56 [95%CI 1.09 to 2.37], p = 0.01). Trastuzumab related CTRCD is associated with significant LAVI morphological remodeling in BC patients.

Background Trastuzumab (TZ) therapy requires careful monitoring of left ventricular (LV) ejection fraction (LVEF) because it can be potentially cardiotoxic. However, LVEF is an imperfect parameter and there is a need to find other variables to predict cardiac dysfunction early. Left atrium (LA) enlargement has proven to be a powerful predictor of adverse outcomes in several disease entities. Hypothesis Baseline LA volume enlargement might predict TZ‐related LV dysfunction. Methods HER2‐positive breast cancer patients receiving TZ and undergoing transthoracic echocardiography at baseline and at follow‐up every 3 months were retrospectively recruited. One‐hundred sixty‐two patients formed the study population. Results Baseline LAVI was dilated in 14 patients (8.6%). Mean follow‐up was 14 ± 4 months. Cardiotoxicity occurred in 24 patients (14.8%). LAVI was an independent predictor of TZ‐induced LV dysfunction in a clinical model, after adjustment for age and hypertension (odds ratio per 5‐mL/m 2 LAVI increase: 1.34, 95% confidence interval: 1.03‐1.82, P = 0.03); and in a hemodynamic model, including ventricular sizes and systolic blood pressure level (odds ratio per 5‐mL/m 2 LAVI increase: 1.34, 95% confidence interval: 1.01‐1.81, P = 0.04). The predicted probability of developing cardiotoxicity increased progressively, in parallel with LAVI values. Conclusions Baseline LA dilatation emerges as a condition associated with the development of cardiotoxicity in HER2‐positive breast cancer patients treated with TZ.

BACKGROUND Adjuvant trastuzumab therapy increases survival rates in patients with early HER2-positive breast cancer, although it can be potentially cardiotoxic. The aim of this study was to evaluate the prevalence of left ventricular (LV) systolic dysfunction; and the relationship between the presence of cardiovascular risk factors, cardiac therapy and/or echocardiographic parameters of systolic function at baseline and the development of cardiotoxicity in such patients. METHODS A total of 227 patients were retrospectively reviewed. Cardiotoxicity was defined as a decrease in LV ejection fraction (EF) below 50% or an absolute decrease of >10 points below the baseline value or any indication of heart failure. Each patient underwent echocardiography at baseline and at follow-up every three months. RESULTS The prevalence of cardiotoxicity was 17.6% (15.4% asymptomatic, 2.2% symptomatic). Patients developing LV dysfunction presented hypertension (P=0.041) and diabetes (P=0.01) and used cardiac therapy at baseline more frequently. Smoke habit, age >50 and use of angiotensin-converting enzyme (ACE)-inhibitors, were independent predictors of cardiac damage. Furthermore, patients with LV dysfunction showed baseline LV end-diastolic volume (EDV) higher than those who did not and baseline EDV (OR=1.02; 95% CI: 1.00-1.04; P=0.027) independently predicted cardiotoxicity with 58 mL/m2 as best cut-off point (AUC=0.65, 95% CI: 0.55-0.75]). CONCLUSIONS The prevalence of trastuzumab-related cardiotoxicity in patients with HER2-positive early breast cancer is relatively frequent, although asymptomatic in most cases. Baseline EDV resulted as independent predictor of cardiotoxicity suggesting that EDV may be more reliable than LVEF to identify patients at higher risk of developing cardiac damage.